Magnetic flux generated when a current flows through a main circuit wiring serves as disturbance of a magnetic sensor, and accurate rotor position information is obtained. A motor drive apparatus controls an operation of a power conversion device outputting a current to an AC motor on the basis of a desired torque command value, and includes a main circuit wiring that is electrically connected to a switching element forming the power conversion device, and through which a DC current or an AC current is transmitted thereto, a magnetic sensor that detects a magnetic flux change of a sensor magnet attached to a rotor of the AC motor, and a controller that calculates a current command value which is output from the power conversion device to the motor on the basis of position information of the rotor detected by the magnetic sensor, in which the controller includes a magnetic flux error correction unit that detects or calculates a magnetic flux component generated by a current flowing through the main circuit wiring.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A motor drive apparatus controlling an operation of a power conversion device outputting a current to a motor on the basis of a desired torque command value, the apparatus comprising: a main circuit wiring that is electrically connected to a switching element forming the power conversion device, and through which a DC current or an AC current is transmitted thereto; a magnetic sensor that detects a magnetic flux change of a sensor magnet attached to a rotor of the motor; and a controller that calculates a current command value which is output from the power conversion device to the motor on the basis of position information of the rotor detected by the magnetic sensor, wherein the controller includes a magnetic flux error correction unit that detects or calculates a magnetic flux component generated by a current flowing through the main circuit wiring and a position correction unit that removes the magnetic flux component generated by the current flowing through the main circuit wiring from an output of the magnetic sensor.
2. The motor drive apparatus according to claim 1 , wherein the magnetic flux error correction unit calculates a magnetic flux component generated by a current flowing through the main circuit wiring on the basis of the magnitude and a direction of the current flowing through the main circuit wiring.
3. The motor drive apparatus according to claim 1 , wherein the magnetic flux error correction unit stores therein position information of the main circuit wiring and the magnetic sensor, and calculates a magnetic flux component generated by a current flowing through the main circuit wiring on the basis of the magnitude and a direction of the current flowing through the main circuit wiring, and the position information.
4. The motor drive apparatus according to claim 1 , wherein the magnetic sensor outputs the magnitude in an in-surface direction of a magnetic flux vector supplied from the sensor magnet.
5. The motor drive apparatus according to claim 1 , wherein the magnetic sensor outputs angle information for a magnetic flux vector supplied from the sensor magnet, and wherein the magnetic flux error correction unit calculates a magnetic flux component generated by a current flowing through the main circuit wiring on the basis of the magnitude and a direction of a current flowing through the main circuit wiring, and the angle information of the magnetic sensor.
6. The motor drive apparatus according to claim 1 , wherein the controller corrects a detection value in the magnetic sensor on the basis of a detection value or a calculation value in the magnetic flux error correction unit.
7. The motor drive apparatus according to claim 1 , wherein correction of a detection value in the magnetic sensor is performed in a case where a current value of the motor is equal to or greater than a predetermined value.
8. The motor drive apparatus according to claim 1 , wherein correction of a detection value in the magnetic sensor is performed only in a case where a voltage vector command value of the power conversion device satisfies a predetermined condition.
9. A motor drive apparatus controlling an operation of a power conversion device outputting a current to an AC motor on the basis of a desired torque command value, the power conversion device including two or more three-phase bridge circuits, the apparatus comprising: a main circuit wiring that is electrically connected to a switching element forming each of the three-phase bridge circuits, and through which a DC current or an AC current is transmitted thereto; a magnetic sensor that detects a magnetic flux change of a sensor magnet attached to a rotor of the AC motor; and a controller that calculates a current command value which is output from the power conversion device to the motor on the basis of position information of the rotor detected by the magnetic sensor, wherein the controller includes a magnetic flux error correction unit that separately detects or calculates magnetic flux components generated by a current flowing through a main circuit wiring connected to one of the three-phase bridge circuits and a current flowing through a main circuit wiring connected to the other three-phase bridge circuit and a position correction unit that removes the magnetic flux components generated by the current flowing through the main circuit wiring from an output of the magnetic sensor.
10. The motor drive apparatus according to claim 9 , wherein the magnetic flux error correction unit stores therein position information of the main circuit wiring and the magnetic sensor, and calculates a magnetic flux component generated by a current flowing through the main circuit wiring on the basis of the magnitude and a direction of the current flowing through the main circuit wiring, and the position information, in a case where both of the three-phase bridge circuits or only one of the three-phase bridge circuit is being operated.
11. An electric power steering device comprising the power conversion device according to claim 1 .
12. An electric power steering device comprising the power conversion device according to claim 9 .
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
June 27, 2016
September 24, 2019
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.